Wind-propelled watercraft

ABSTRACT

The invention relates to a wind-propelled watercraft by means of which in contrast to the conventional solutions the wind forces can be better utilized for the propulsion, and the turning moments about the longitudinal axis acting on the body of the watercraft and the hull, respectively can be reduced. With this, a sheet element is held with at least one stay rope in close proximity to the body of the watercraft, and the one or else a plurality of stay ropes are attached to at least three points of the sheet element spaced to one another. In addition, the point of application of force of the one or else a plurality of stay ropes on the body of the watercraft can be varied depending on the wind direction and direction of motion.

[0001] The invention relates to wind-propelled watercrafts in which atleast one sheet element is held with at least one stay rope on a body ofthe watercraft, in particular a hull. The invention can be employed moreparticularly with sail ships and other watercrafts as well solely or incombination with additional conventional drives.

[0002] Heretofore, it is usual for the propulsion of watercrafts andother vehicles as well to take advantage of wind power to use one or aplurality of sails made of textile materials which are stabilized atleast on one mast, and also in addition with so-called booms or yards.Such sails will be aligned in accordance with the wind direction or thedesired direction of motion, and utilize at least one component of thewind power which as a rule merely provides one portion of the total windpower for generating propulsion.

[0003] With this form, however, turning moments are also acting in thelongitudinal axis in which the mast(s) is (are) arranged as well whichmore or less cause an oblique position about the longitudinal axis of ahull and body of the watercraft, respectively. To actively oppose thiseffect leeboards and cost effective keel constructions, respectively areemployed with sail ships and sailing boats, respectively according tothe size of the used sail areas. Since limits are set for this, however,the direction of motion and wind direction can be utilized in anoptimized manner to each other only to some extent, and the ship can beadequately steered such that frequently crossing is required withunfavourable wind directions which of course results in an extension ofthe duration of travel toward a particular destination.

[0004] With high wind velocities in particular the mast and masts,respectively is (are) providing a weakest point, and in the case thatthe mast and masts, respectively is (are) breaking sailing boats andsail ships are nearly incapable of manoeuvring and exposed to therigours of weather and water without any resistance because of thefailed propulsion such that a high potential of danger is given to theship's crew.

[0005] For avoiding said dangers with high wind velocities it can berequired to reduce at least one portion of the sail area by reefing sailin order to decrease the forces and turning moments acting on the mastsof the ship. Thereby, of course the driving speed of such a boat andship, respectively is reducing.

[0006] Therefore, it is an object of the invention to providewind-propelled watercrafts by means of which the wind forces can bebetter used for the propulsion, and the turning moments acting about thelongitudinal axis on the body of the watercraft and hull, respectivelycan be decreased.

[0007] In accordance with the invention this object is solved with thefeatures of claim 1. Advantageous embodiments and improvements of theinvention can be implemented with the features mentioned in thesubordinate claims.

[0008] The watercraft according to the invention uses at least a sheetelement which is formed similar to a conventional sail or a sufficientlywell-known kite as well to increase the propulsion due to the action ofwind force, and to largely reduce the tilting moments already mentioned.Such a sheet element which should have a small mass, if possible, isheld with at least one stay rope in close proximity to the body of thewatercraft wherein the stay rope is attached to the sheet element on atleast three points spaced apart from each other to allow the sheetelement to be deflected and aligned in the vertical and horizontaldirections in order to enable an optimum alignment of the sheet elementaccording to the desired direction of motion under consideration of therespective wind direction.

[0009] This can be taking things so far that by means of a stay rope,control the sheet element will be aligned and brought into the wind suchthat it is allowed to be moved in the vertical direction upwardly anddownwardly, respectively within wind layers having higher windvelocities.

[0010] Such an element and a plurality of elements as well, wherein aplurality of sheet elements are preferably connected to each other, canbe made of a lightweight sheet material. Favourably, flexible materialsmay also be employed for such sheet elements which deform themselves dueto the wind force then, and equivalently increase the drag factor (EW)such that the component of force usable for the propulsion is alsoincreased.

[0011] Compressed gas containing chambers can be arranged, formed andalso secured, respectively on the one sheet element and a plurality ofsheet elements, respectively for increasing the stability as well andlift, as the case may be, for such a sheet element. Such a compressedgas containing chamber which is formed and arranged, respectively inclose proximity to the sheet element, and in which compressed gas iscontained results in an increase of the stability of such a sheetelement. Such compressed gas containing chambers can also achieve asupporting function similar to rigid frame constructions with a smallermass for sheet elements. By means of one or a plurality of compressedgas containing chamber the form and shape of the sheet element can bedefined.

[0012] On the compressed gas containing chambers fittings with valvescan be provided which allow charging and discharging the compressed gascontaining chambers, respectively.

[0013] It is more especially advantageous to charge the compressed gascontaining chambers with gas having a lower density than air such that alifting force component can be obtained for the sheet elements.Appropriate charging gases for example are helium, but hydrogen as well.With a sufficiently great volume and sufficient charging with such a gashaving a relatively lower density it can be achieved that the liftingforce is at least greater than or equal to the weight of the sheetelement. However, it should also be greater than or equal to theproportional weight of the stay rope(s), if possible. In this case, thesheet element is freely floating in the atmospheric air, and it isallowed to be significantly easier manoeuvred and aligned relative tothe prevailing wind direction. In addition, thus it is prevented fromdropping on the ground and water surface, respectively and then anexpense action is required to bring the sheet element into the windagain.

[0014] However, similar to a conventional captive balloon, thecompressed gas containing chamber(s) can also be charged with a gas oflower density, and such a sheet element is allowed to be suspendedthereon. In case that a two-dimensional element made of a flexiblematerial has been used it is favourable to use at least two of suchcompressed gas containing chambers in the form of a captive balloon.

[0015] However, the compressed gas containing chambers can also beprovided with apertures by means of which they can be charged with airdue to a dynamic pressure when the sheet element is directed into thewind.

[0016] For enabling the first already mentioned alignment of such sheetelements both in the vertical direction and horizontal direction it isfavourable to vary the length of the stay ropes each used between thesheet element and body of the watercraft and hull, respectively. On thatoccasion, each stay rope can be lengthened and also shortened,respectively one by one individually. It is also possible, however, forsuch two stay ropes each which are arranged on the sheet element inhorizontal and vertical planes, respectively, to be lengthened andshortened, respectively with the same length in the opposite direction.

[0017] By simultaneously uniform lengthening or shortening all stayropes the sheet element can be brought into the wind or can be hauledin.

[0018] The elements used to vary the length of the stay ropes areallowed to be pulleys, for example, which the respective stay rope canbe wound up on and unwound therefrom, respectively. Such pulleys can beconstructed such as the elements which in the sailor's language aredesignated as “winches”.

[0019] The propulsion can be manually carried out in a controlled mannerby means of electric motors and backgeared motors, respectively in whichthe control of the sheet element, thus shortening and also lengtheningthe stay ropes can occur under consideration of the measured winddirection, the desired direction of motion and/or else as the case maybe under consideration of the tensile forces measured on the individualstay ropes by means of an electronic control.

[0020] In particular, for each avoiding and reducing the turning moments(tilting moments) acting about the longitudinal axis it is advantageousto vary the point of application of force of the stay ropes on the bodyof the watercraft and hull, respectively under consideration of therespective wind direction and direction of motion. This appliesindependently to whether with respect to a plurality of stay ropes theseare secured to the body of the watercraft in close proximity to eachother or whether a common virtual point of application of force resultsfrom the force vectors of these stay ropes.

[0021] With this, various solutions are possible.

[0022] Thus, on the one hand it is possible to adequately adapt thepoint of application of force of the stay ropes on the body of thewatercraft by means of a guide. In the most simple case such a guide canbe a hoop being orthogonally aligned with the longitudinal axis of thebody of the watercraft which the stay rope(s) is (are) lead about suchthat according to the alignment of the sheet element with respect to thelongitudinal axis of the point of application of force will beautomatically displaced. It is more especially advantageous for thistransversal hoop to be curvedly formed such that the convex contour ofsuch a hoop is facing upwardly and in the direction of the front of thebody of the watercraft (direction of hoop) respectively and obliquelyforwardly.

[0023] Such a solution can be additionally improved when such atransversal guide is received within two guides aligned in parallel withthe longitudinal axis of the body of the watercraft, and is allowed tobe displaced by means of such guides along the longitudinal axis of thebody of the watercraft.

[0024] Another alternative to vary the point of application of force ofthe stay ropes is to provide it excentrically on a rotary table which isrotatable with its centre about a vertically aligned rotational axissuch that the point of application of force with respect to thelongitudinal axis of the body of the watercraft is allowed to beautomatically varied in its position due to the excentric arrangementand the turning moments correspondingly acting. However, such avariation of position can also be implemented in a controlled mannerwith an equivalent rotary drive for the rotary table.

[0025] A third alternative of varying the point of application of forcefor the stay rope(s) is in the use of a lever shaped jib boom which onone side comprises a link by means of which the lever shaped jib boom isattached, e.g., to the longitudinal axis of the body of the watercraft.Then, the stay rope(s) are secured in a distance preferred at the end ofthis jib boom such that during pivoting the jib boom about the link itcan be achieved a variation of the position of the force applicationpoint of the stay rope(s) with respect to the longitudinal axis of thebody of the watercraft. Ball and socket joints and universal joints, forexample, are suitable as a link which can also be secured inside a guidewhich is aligned at right angles to the longitudinal axis.

[0026] The point of application of force can also be varied with respectto the so-called lateral centre of pressure, and selectively adjustedsuch as still to be described in the following. With the lateral centreof pressure it deals with the area related centre of inertia of theprojected area on the longitudinal axis of the watercraft. It is allowedto coincide with the mean transversal axis, and the transversal axis canbe located close to the lateral centre of pressure, respectively suchthat this as well can be used as reference for the point of applicationof force in a simplified manner.

[0027] By means of selectively influencing the position of the point ofapplication of force with respect to the lateral centre of pressure itis also allowed for the direction of motion (course) of the watercraftto be influenced. Thus, with a position of the point of application offorce in front of the lateral centre of pressure the watercraft can beturned into the direction of the side sheltered from the wind (lee side)and into the direction to the side facing towards the wind (weatherside) during positioning the point of application of force in theopposite direction, thus behind the lateral centre of pressure (alwaysviewed in the direction of motion).

[0028] By influencing the position of the point of application of forceof the sheet element orthogonally to the longitudinal axis and directionof motion, respectively the heeling can be selectively influenced in acompletely compensated manner. Thus, in certain cases even a negativeheeling can be met if the point of application of force has beendisplaced quite far in the direction of the side sheltered from thewind, for example.

[0029] In addition to the already mentioned elements for varying theeffective lengths of the stay rope(s) additional deflection pulleys canbe disposed between the point of application of force and the sheetelements. The stay ropes can be deflected through these deflectionpulleys which is favourably effecting during the variation of positionof the point of application of force, on the one hand. These deflectionpulleys can also be displaced, on the other hand, whereby a unique andadditional variation of length of a plurality of stay ropes can beachieved in a relatively simple manner and without any requiredactuating forces.

[0030] For a sail-shaped and kite-shaped sheet element, respectivelywhich has been stretched in a two-dimensional manner using the alreadymentioned compressed gas containing chambers if possible, the mostdifferent geometric forms can be employed wherein optimizing the shapesof the sheet elements for the respective application can also be carriedout under consideration of the design of the body of the watercraftused.

[0031] For a sufficient manoeuvrability of the sheet element it isadvantageous to use at least three stay ropes being variable in itseffective length independently from each other, which are attached tothe body of the watercraft and to the sheet element then. Mounting onthe sheet element is achieved such that the three mounting points of thestay ropes are spanning a triangle, and thus with lengthening andshortening, respectively the effective lengths of the three stay ropesthe sheet element can be moved both in horizontal and verticaldirections as well by means of the attacking wind force, and in additionthe angle of attack is variable with respect to the prevailing winddirection.

[0032] It is more favourably to use four stay ropes which provide theconnection between the sheet element and the body of the watercraft. Onthat occasion, the four stay ropes are attached to the sheet elementsuch that the mounting points are spanning a square, if possible,wherein each two mounting points are in a common horizontal plane, andthe other two mounting points are in a vertical plane. For manoeuvringthe sheet element at least lengthening and shortening, respectively of astay rope is required. However, the stay ropes which mounting points areon the sheet element in a plane can also be lengthened and shortenedwith the same length if possible in opposite direction each. If thismodification will be selected, the actuation power each required can becorrespondingly reduced such that manual actuating is readily possible.

[0033] With the invention the keel constructions being common forwatercrafts heretofore, first are allowed to be smaller dimensioned andeven more substituted by more cost effectively leeboards since theturning moments acting about the longitudinal axis will be significantlyreduced.

[0034] Application in average situations is also possible, e.g., if witha conventional sail ship or sailing boat a mast has been broken and awind propulsion according to the invention which is onboard can berapidly and simply employed and provide the propulsion andmanoeuvrability.

[0035] In additions it is advantageous to provide at least onehydrodynamically effective element, which can also be designated withthe term “hydrofoil”, on the body of the watercraft. On that occasion,such an element is located beneath the floating line on the body of thewatercraft and allows stabilizing the watercraft during the progressivemovement.

[0036] It is more especially advantageous that such a hydrodynamicallyeffective element can be pivoted about an axis such that a lift force ora depression force can be adjusted for the watercraft.

[0037] However, these hydrodynamically effective elements should bearranged such that symmetrical force relations occur with respect to thelongitudinal axis of the watercraft. Thus, for example, two suchelements can be arranged in the same level on the two outer sides of thebody of the watercraft.

[0038] Favourably, the pivoting angle of the hydrodynamically effectiveelements can also be adjusted depending on the vehicle speed and/ortensile force of the sheet element. In particular, during immediatelyoccurring gusts of wind, thus it can be ensured that the body of thewatercraft will be carried in the water also during extreme situations.With this, the pivoting angle of the hydrodynamically effective elementscan be adjusted by a mechanical coupling by means of the tensile forceacting on the stay ropes or point of application of force.

[0039] These elements are allowed to be formed similar to wings andeither aligned horizontally or in an angle slightly inclined toward thehorizontal.

[0040] The aerodynamic properties of the sheet element can be influencedby effecting the three-dimensional form which can be achieved by meansof the stay ropes, and if the case may of additional stay ropes. Inaddition, supplementary aerodynamically effective elements can beattached to the sheet element. These aerodynamically effective elementsare allowed to be pivotally secured on the sheet element and formed in aflap shape, for example, such that being more or less put upright theycause lift or side forces on the sheet element effected by thecorrespondingly increased flow resistance against the attacking windaccording to the adjusted angle and the corresponding arrangement, andthus allowing for the position of the sheet element to be manipulatedwith respect to the body of the watercraft and the wind direction. Theadjustment of the pivoting angle of these aerodynamically effectiveelements can be achieved by means of equivalent ropes as well, forexample, which are guided toward the body of the watercraft.

[0041] It can also be of advantage if airflow breakaway elements(winglets) are provided on the outer edges of the sheet element whichare allowed to cause an improvement of the aerodynamics as well.

[0042] To avoid situations of danger additional elements protecting fromoverload can be used. These elements ensure that with exceeding apredeterminable maximum tensile force on the one or a plurality of stayropes this force cannot attack on the body of the watercraft in fullsize. A possibility to oppose these overload conditions is in that toprovide the stay ropes with a spring, a damper or a spring dampingsystem wherein the spring and damper characteristics should be adjustedsuch that the equivalent spring or damping forces become effective untilexceeding the threshold already mentioned, and for example a tensionspring having a degressive spring characteristic should be selected suchthat the correlative tensile forces of such an element protecting fromoverload can be reduced again.

[0043] Another alternative for an element protecting from overload is inthe use of sliding clutches which are provided at winches, for example,to influence the length of the stay ropes as the case may be.

[0044] Another advantageous aspect of the watercraft according to theinvention can be equipped with a manipulable leeboard. Such a leeboardis allowed to be reciprocated in the vertical direction such that theeffective area can be adjusted as the occurring heeling on the vehicleaccording to the invention can be completely, however, at least largelycompensated.

[0045] However, such a leeboard can also be deflected with respect tothe longitudinal axis of the body of the watercraft such that it isallowed to completely take over or support the function of aconventional rudder. In addition, with such a leeboard it is allowed togo higher by the wind (more height running).

[0046] To increase the safety at least one sensor string can be attachedto the sheet element which is guided therefrom to the body of thewatercraft. By means of these sensor strings with touching them thepropulsion of the watercraft can be influenced, and such propulsion canbe drastically reduced by the correlative influence of theaerodynamically effective surfaces and shape of the sheet element in avery short time. Preferably, two sensor strings can be attached to theouter edges of the sheet element.

[0047] Controlling a watercraft according to the invention can befacilitated by different ways and completely automated with adequateexpense as well.

[0048] Thus, measured values detected with various sensors can beprocessed in control electronics, and at least the position of the sheetelement can be influenced with respect to the desired direction ofmotion and wind direction with this control electronics.

[0049] However, controlling a vehicle according to the invention, canalso be influenced purely mechanically in a relatively simple mannerwith sling elements for stay ropes which are provided on the body of thewatercraft.

[0050] With these sling elements for stay ropes which are arranged onthe body of the watercraft between the respective mounting point of thecorresponding stay rope and the sheet element, influencing the positionof the sheet element can be achieved. In the most simple case a slingelement for stay ropes is allowed to be a vertically aligned rodattached to the body of the watercraft which the laterally drifting stayrope abuts against during equivalent movement of the sheet body whichresults in a relatively shortening of the stay rope which prevents afurther movement of the sheet element into the direction which is notdesired.

[0051] However, a sling element for stay ropes can also be designed inthe form of a hoop which is attached to the body of the watercraft. Therespective stay rope is guided through this hoop such that an abuttinglimit is provided on both sides in the horizontal direction and upwardlyin the vertical direction.

[0052] The sheet element for a watercraft according to the invention isallowed to comprise at least one compressed gas containing chamber. Thecompressed gas containing chamber can be a part of the sheet element orbe connected with the sheet element. Such a compressed gas containingchamber should be able to be charged from a gas accumulator tank inwhich compressed gas being preferably helium is contained via a firstconduit which is connected and can be connected to the compressed gascontaining chamber, respectively. On that occasion, a defined gas volumeis to be filled in into the compressed gas containing chamber which issufficient to effect a lifting force for the complete sheet elementwhich should be greater than or equal to the component of thegravitational force of the sheet element.

[0053] The connection between the compressed gas accumulator which canbe a conventional gas bottle, and the compressed gas containing chamberon the sheet element can be achieved by a valve and can be disconnectedtherefrom again. Then, the valve can be arranged in close proximity onthe outlet of the compressed gas accumulator but also in the firstconduit, and can be manually opened and closed in a most simple manner.

[0054] However, a valve which automatically closes depending on theinternal pressure in the compressed gas containing chamber can also beemployed with reaching a predeterminable internal pressure.

[0055] For recirculating gas from the compressed gas containing-chamberat least a second conduit should be present which in an alternative ispassing in parallel to the first conduit already mentioned, and whichcan also be connected to the at least one compressed gas containingchamber wherein this second conduit is allowed to lead into a secondcompressed gas accumulator or into a second port of that one compressedgas accumulator connected to the compressed gas containing chamber aswell.

[0056] However, the second conduit has not to be absolutely connected inclose proximity with a compressed gas containing chamber, but it is alsoallowed to be connected to the first conduit wherein the port to thefirst conduit can be achieved through a so-called T-piece.

[0057] The second conduit can also represent a by-pass around the valvealready mentioned to the first conduit, however, wherein in this casethe gas recirculated from the compressed gas containing chamber is to becarried into the one compressed gas accumulator.

[0058] As a rule, at least in such cases in which the recirculated gasis to be carried into the gas accumulator which has also been used forcharging the compressed gas containing chamber, in the second conduit acompressor can be disposed the induction side of which is connected tothe portion of the second conduit towards the compressed gas containingchamber, and the delivery side of which is connected to the portion ofthe second conduit which communicates with the gas accumulator.

[0059] Compressors in the most different well-known forms are possible,however, wherein on the delivery side a gas pressure should be availableby means of which it is ensured that the compressed gas accumulator canbe charged again with the recirculated gas.

[0060] In the most simple cases manually actuated compressors such ashand pumps or piston compressors can be employed.

[0061] If two gas accumulators are used, then the second gas accumulatorinto which the gas from the compressed gas containing chamber is againrecirculated can be differently dimensioned such that inside thereof arelatively low internal pressure occurs with the recirculated gaswherein the already mentioned compressor can be abandoned as the casemay be.

[0062] The recirculated gas temporarily stored in the second compressedgas accumulator is thus allowed to be recirculated from this secondcompressed gas accumulator into a first compressed gas accumulator andto be compressed higher at any times by means of an equivalentcompressor.

[0063] The first conduit already mentioned can be temporally connectedto the compressed gas containing chamber for charging and recirculatingthe gas wherein in this case a lockable connecting branch should beprovided on such a compressed gas containing chamber.

[0064] As the required internal pressures in the compressed gascontaining chamber are relatively low, however, it is also possible tostationarily connect a relatively weak dimensioned first conduit havinga low mass to the compressed gas containing chamber such that the firstconduit with a sufficient length has not to be separated from the sheetelement during the progressive movement of the watercraft.

[0065] The first conduit should be made of flexible material not only inthis case such that handling is facilitated.

[0066] However, the first conduit connecting the compressed gascontaining chamber and a compressed gas accumulator can also be guidedas a by-pass around a compressor wherein the gas stream can be guidedthrough this first conduit or the compressor by means of at least onetwo-way valve. The second conduit can be formed in this case by thecompressor with its two ports. The first conduit can be guided throughthe compressor housing.

[0067] The compressed gas accumulator utilized at least for charging theone and also a plurality of compressed gas containing chambers,respectively should have an internal pressure of gas before and duringcharging which is greater than or equal to the required internalpressure in the pressure chamber and in the pressure chambers,respectively.

[0068] All the components required for charging and recirculating thegas are allowed to be carried with the wind-propelled watercraft suchthat replenishing the compressed gas containing chamber is also possibleduring the further movement. At least one of the compressed gasaccumulators should be able for this to be attached to the vehiclewherein the attachment should be formed such that the equivalentcompressed gas accumulator can be carried separately of the vehicle to atank installation for replenishing with gas.

[0069] In the following, the invention shall be explained in more detailaccording to embodiments in which

[0070]FIG. 1 shows an embodiment of a sheet element which can beemployed on a watercraft according to the invention;

[0071]FIG. 2 shows another embodiment of a sheet element having a kiteshape;

[0072]FIG. 3 illustrates a top view upon a body of the watercraft withan embodiment for a wind propulsion according to the invention;

[0073]FIG. 3a illustrates an enlarged section X from FIG. 3;

[0074]FIG. 3b shows a jib boom which can be employed with the embodimentaccording to FIG. 3;

[0075]FIG. 4 illustrates a top view of another embodiment with a body ofthe watercraft;

[0076]FIG. 4a shows the enlarged section Y from FIG. 4;

[0077]FIG. 4b shows an embodiment of an element suitable for varying thelength of stay ropes;

[0078]FIG. 5 shows a top view of another embodiment for carrying outguides on a body of the watercraft;

[0079]FIG. 5a shows a sectional view along A-A from FIG. 5;

[0080]FIG. 5b illustrates the section Z as an enlargement from FIG. 5a;

[0081]FIG. 6 shows another embodiment of wind propulsion in a top view;

[0082]FIG. 7 shows a top view upon a body of the watercraft having a jibboom for varying the point of application of force;

[0083]FIG. 7a shows a front view upon an embodiment according to FIG. 7;

[0084]FIG. 7b shows the enlargement of the sections W and W′ from FIG.7a;

[0085]FIG. 8 shows a top view upon-another embodiment of a windpropulsion; FIG. 8a shows a side view of FIG. 8;

[0086]FIG. 9 shows a diagrammatic view of an embodiment of a windpropulsion on a sailing boat;

[0087]FIG. 10 shows a top view upon a diagrammatically illustrated bodyof the watercraft;

[0088]FIG. 11 shows three embodiments of modification for sheet elementsand the possible alignment thereof toward the wind;

[0089]FIG. 12 shows three embodiments for adjusted forms of a sheetelement under consideration of the wind force;

[0090]FIG. 13 shows a diagrammatic view of a sheet element havingaerodynamically effective elements;

[0091]FIG. 14 shows a diagrammatic view of a sling element for stayropes disposed on a body of the watercraft in three views;

[0092]FIG. 15 shows diagrammatically a body of the watercraft which isconnected to a sheet element by means of a stay rope;

[0093]FIG. 16 shows an embodiment of a sheet element comprising acompressed gas containing chamber and a connecting branch;

[0094]FIG. 17 shows the structure of an embodiment of a gas supply andrecirculation according to the invention in a diagrammatic form;

[0095]FIG. 18 shows a second embodiment of a gas supply andrecirculation according to the invention;

[0096]FIG. 19 shows a third embodiment of a gas supply and recirculationto be used according to the invention;

[0097]FIG. 20 shows an embodiment of a gas supply and recirculation tobe used according to the invention with two gas accumulators.

[0098] In the FIGS. 1 and 2 are shown two possible embodiments for sheetelements 1 as can be employed in the sail and kite shapes as well,respectively for a wind propulsion according to the invention.

[0099] With the embodiment according to FIG. 1 the sheet element 1 isattached with four stay ropes 2 to the not illustrated body 3 of thewatercraft wherein the length of the four stay ropes 2 can be variedeach individually, if possible in order to move the sheet element 1 inthe most different directions and align in accordance with the desireddirection of motion with a present wind direction.

[0100] In this embodiment the sheet element 1 is made of a flexiblematerial, for example a film and a textile fabric, respectively which atleast are gasproof. The at least two-layered sheet element 1 sealed atthe edges defines a compressed gas containing chamber 7 in the completeinterior thereof which, e.g., is filled with helium. Charging thecompressed gas containing chamber 7 is achieved under consideration ofthe chamber volume and the masses of the sheet element 1, the massthereof and the shared mass of the stay ropes 1 in so far that a liftingforce can be generated which is greater than the correspondinggravitational force such that the sheet element 1 will be readily heldin the atmosphere as permitted by the respective length of the stayropes 2.

[0101] The sheet element 1 shown herein approximately corresponds to thecontour and cross-sectional geometry, respectively of a conventionalwing of an aircraft which makes effecting a dynamic lift componentcaused by flow conditions on the element 1 in addition to the staticlift. By adequate adjusting the lengths of the four stay ropes 2 it isallowed to be aligned into the wind such that, if possible, a great airresistance is achieved with a great effective acting surface, ifpossible which can be opposed to the wind.

[0102] However, more than four stay ropes 2 as illustrated herein canalso be employed wherein this may be advantageous with large surfacedimensioned sheet elements 1.

[0103] The embodiment of a sheet element 1 shown in FIG. 2 is similar tothe design of conventional kites, and it is immediately attached to thebody 3 of the watercraft also not shown with merely one stay rope 2. Thestay rope 2 runs starting from a hitch 20 in three individual lineswhich are attached to edge points of the kite-shaped sheet element 1,wherein the sheet element 1 comprises a frame construction 12 whichpreferably may be made of a lightweight and solid material. On thatoccasion, it is allowed to concern with carbon fiber reinforced plasticsin tube or rod shapes which adequately stabilize a textile fabric andkeep it in form.

[0104] The variation of the respective length of one and a plurality ofstay rope(s) 2 as well respectively can be implemented in various mannerwhich it shall be better explained by way of example with the subsequentdescription of another figures.

[0105] Thus, FIG. 3 being a top view upon a diagrammatically illustratedbody 3 of the watercraft shows a possibility with four stay ropes 2 inall which each can be individually varied with elements 5 in itseffective length between the body 3 of the watercraft and the sheetelement 1 not shown.

[0106] From the illustrations shown in FIGS. 3, 3a and 3 b severalvariations can be derived by a corresponding explanation.

[0107] Thus, the elements 5 which are commonly formed as pulleys whichthe respective stay ropes 2 can be wound up on and unwound therefrom,respectively are allowed to be anchored on the body 3 of the watercraft.From these pulleys 5 the four stay ropes 2 are guided over a deflectionpulley 6′ which herein is modified as a so-called four-pulley block orwith two double blocks, over further four deflection pulleys 6 toward adeflection element which represents the actual point 4 of application offorce of the stay ropes 2 on the body 3 of the watercraft, and therefromto the sheet element 1 not shown.

[0108] On that occasion, the force application point 4 and the sheetelement 1 are selectively drifting caused either by lengthening andshortening, respectively the individual stay ropes 1 due to winding upand unwinding, respectively on the pulleys 5. It is also allowed todrift in that the double block 6′ as deflection pulleys for the stayropes 2 will be varied its position. In particular with the descriptionof the FIGS. 3a and 3 b it shall be still referred back topossibilities, for example, on how this can be achieved.

[0109] In FIG. 3a the detail X from FIG. 3 is shown as an enlargement.

[0110] Then, several arrows have been drawn especially on the deflectionpulley system 6′ herein used as a four-pulley block to indicate thepossibilities for influencing the position of the point 4 of forceapplication. Thus, it is possible to provide shifting in parallel ororthogonally to the longitudinal axis of the body 3 of the watercraft aswell as a pitch circle diameter shifting as indicated with thecorrespondingly formed double arrow. The latter can be achieved with anarrangement on a rotary table 11 which can be distorted about asymmetrically arranged rotational axis. Then, the deflection system 6′is excentrically disposed on the rotary table 11 and moves on a circlepath during rotating the rotary table.

[0111] In another variant the use of a lever arm and jib boom 10,respectively secured to a joint 16 on the body 3 of the watercraft whichthe deflection system 6′ is attached to as two double blocks. The jibboom 10 can be automatically adequately pivoted, selectively manuallybut also mechanically at the upper end due to the deflection of thesheet element 1 such that the deflection point for the stay ropes 2,which is predetermined by the deflection system 6′, is driftingtherewith according to the movement of the jib boom 10.

[0112] In particular, in FIG. 3a on the bottom of the body 3 of thewatercraft anchored eyes can be seen which the four another deflectionpulleys 6 are attached to, which one stay rope 2 each is furtherdeflected on.

[0113] With the embodiment of a control shown in FIGS. 4, 4a and 4 b forthe wind propulsion according to the invention four stay ropes 2 havebeen used again which are guided on a sheet element 1 and attachedthereto which can be formed such as according to FIG. 1. Each individualstay rope 2 is guided through a separate deflection pulley 6 toward anelement 5 by means of which the respective length of the stay rope 2 canbe varied. Such an element 5 can be formed as indicated with FIG. 4b,for example, as a conventional winch as it is used on sailing boats andsail ships, respectively, and is allowed to comprise a free-wheel andbrake. Additionally, a crank can be joined by means of which therespective stay rope can be wound up and unwound.

[0114] The force application point 4 for the four stay ropes on the body3 of the watercraft can be varied by means of a deflection system, forexample a pulley system which in the sailor's language is designated asa four-pulley block, and the position thereof by varying the length ofthe four stay ropes 2 under consideration of the desired direction ofmotion and the present wind direction.

[0115] The enlarged illustration of the section Y in FIG. 4a isintimating herein that eyes 13 are anchored on the bottom of the body 3of the watercraft as well, and which serve for supporting the deflectionpulleys 6.

[0116] With the embodiments according to FIGS. 5, 5a and 5 b guides 8and 9 are employed to vary the position of the force application point 4with respect to the longitudinal and transversal axes of the body 3 ofthe watercraft.

[0117] Thus, two longitudinal guides 9 which are aligned in parallel tothe longitudinal axis of the body 3 of the watercraft are disposed atthe edges of the body 3 of the watercraft. In these longitudinal guides9 a transversal guide 8 is held and guided such that it can be displacedover the total length of the body 3 of the watercraft, as required.

[0118] However, only one of the guides 8 or 9 can be employed as well.

[0119] As can be seen in the sectional view 5 a along the section A-A,however one or a plurality of stay ropes 2 as well are guided to thedeflection pulleys 6 disposed on a guide element 14 guided on thetransversal guide 8 or in close proximity toward this guide element 14with the deflection pulleys 6 abandoned, and are attached thereto.

[0120] As can be better seen in the enlarged sectional view Z in FIG. 5bthe guide element 14 can be reciprocated along the transversal guide 8which it is guided on in a form-fit manner and held as indicated withdouble arrow such that the force application point 4 can be variedorthogonally to the longitudinal axis of the body 3 of the watercraft bymeans of shifting the guide element 14. If the transversal guide 8 nowis displaced along the longitudinal guides 9 a further variation of theposition of the force application point 4 can be obtained.

[0121] With the embodiment shown in FIG. 6 relating to a possibility forvarying the effective length of the stay ropes 2 between the body 3 ofthe watercraft and sheet element 1 not shown as well, a double lever 5has been used which ends each a stay rope 2 is attached to. Then, thedouble lever arm 5 can be distorted about an axis 15 of rotation suchthat according to the distortion angle of the double lever 5 about therotational axis the right and the left stay ropes 2, respectively eithercan be lengthened or shortened. The stay ropes are guided to the sheetelement 1 around one deflection pulley 6 each which can be formed hereas a double block. On that occasion, this deflection pulley system 6 isallowed to represent the force application point 4.

[0122] With the embodiment shown in FIGS. 7, 7a and 7 b a jib boom 10,which is attached to the body 3 of the watercraft with a joint 16, isused for varying the position of the force application point 4 for thestay ropes.

[0123] The joint 16 is preferably a ball and socket joint and auniversal joint, respectively by means of which the jib boom 10 can bepivoted into the most different directions.

[0124] The stay ropes 2 are slung to the opposite end of the jib boom 10with respect to the joint 16 wherein the jib boom 16 is allowed to havea length which can protrude beyond the maximum extension of the body 3of the watercraft. Thus, the tilting moment can be further reduced bymore appropriately lever relations.

[0125] As indicated in FIG. 7a the jib boom 10 can be held and alignedwith at least one and preferably two (in opposition to the illustration)rope systems in the form of sheets as such elements are commonlydesignated in the sailor's language.

[0126] In FIG. 7b sections W and W from FIG. 7a are shown to indicatethe configuration of the joint 16 with its fixation on the body 3 of thewatercraft and slinging the stay ropes 2 on the jib boom 10.

[0127] With the embodiment shown in FIGS. 8 and 8a for a possibility tovary the length of stay ropes 2 in principle there are two alternativesfor influencing the effective lengths of the individual stay ropes 2which can be performed and used together, however individually as well.

[0128] Thus, each of the two stay ropes 2 herein are wound up on apulley 5 as a “winch” and guided through a deflection pulley systemherein comprising four, however at least two deflection pulleys 6.

[0129] As can be appreciated from the top view according to FIG. 8 atleast two of the deflection pulleys 6 can be translationally displacedforth and back.

[0130] As can be clearly seen from the side view according to FIG. 8athese deflection pulleys 6 are guided in a form-fit manner and kepttogether with one pedal 19 each on a guide 18. When the pedals 19 aretranslationally moved either forth and back along the guide 18 which isattached to the body 3 of the watercraft then the effective length ofthe respective stay rope 2 will be adequately shortened or lengthened.

[0131] In FIG. 9 is shown a sailing boat with a hull as a body 3 of thewatercraft having a leeboard 21 and a conventional rudder 22. Four stayropes 2 are slung on the body 3 of the watercraft and at the other endsattached to a sheet element 1 in the form of a textile sail. At the edgeof this sail-shaped sheet element 1 an encircling compressed gascontaining chamber 7 is formed which can also comprise a plurality ofseparated individual chambers in which compressed gas is contained. Withsuch a compressed gas containing chamber 7 a frame and stabilizationfunction for a flexible sheet element 1 is achieved. The stability canbe further increased as indicated with additional rod-shaped elementsand also by means of an adequate chamber design, respectively.

[0132] The length of the four stay ropes can be varied in a mostdifferent form for example with one of the already previously describedsystems.

[0133] In FIG. 10 is diagrammatically shown a top view upon a body 3 ofthe watercraft for an embodiment of the watercraft according to theinvention. On that occasion, the hatched area which can extend over thetotal width of the body 3 of the watercraft and also beyond as the casemay be, and which is arranged in the area of the drawn transversal axisof the body 3 of the watercraft herein represents the surface in whichthe point of application of force can be positioned by means of guides 8and 9 as shown in FIGS. 5a and 5 b in order to minimize the heeling andto be able to achieve an optimum driving speed. This area is allowed tobe circular when a rotary table or a jib boom 10 are used.

[0134] The effects which can be achieved by adequately positioning thepoint of application of force are mentioned in the general part of thedescription.

[0135] In FIG. 11 three embodiments relating to the forms ofmodification of the sheet elements are illustrated wherein theindividual cross-sections are discernible herein. With these embodimentsthe construction of the sheet elements 1 is based on the shapes knownfrom wings of aircrafts, and sheet elements 1 thus formed are allowed tobe aligned with respect to the wind as shown in FIG. 11 such that onthese sheet elements 1 a lifting component is generated with the windwhich can be used for the propulsion of the watercraft through the stayropes 2 not shown herein. By means of the different modifications asshown in FIG. 11 different propulsion forces acting as a tensile forceon the point of application of force can be implemented by thecorrespondingly varied flow relations.

[0136] If sheet elements 1 are used in the modification forms as shownin FIG. 11 the so-called Ca coefficient (lift coefficient of a profile)is of importance in addition to the Cd factor, and just the Cacoefficient should be great in these cases, and accordingly the dragfactor should be kept small.

[0137] By influencing the three-dimensional form with the profile theposition, aerodynamic properties and accordingly also the acting forcescan be influenced with the correspondingly occurring Ca coefficient andCd factor.

[0138] During the travel of the watercraft the shape of the sheetelements 1 can also be influenced by varying the internal pressurewithin the compressed gas containing chambers 7.

[0139] In FIG. 12 there are shown three further embodiments for adjustedshapes of a sheet element 1 which can be adjusted by varying the lengthof individual stay ropes 2 and by means of which differently great windforces can be taken into account.

[0140] Thus, the shape shown above can be met with small up to mean windforces to keep to aerodynamic relations by means of this shape, which amaximum propulsion can be achieved with.

[0141] With setting the shape of a sheet element 1 as shown in the meanillustration, the propulsion force can be reduced at greater windforces, and with quite high wind forces such as occurring with gusts ofwind, a variation of the shape of the sheet element 1 as shown in thebottom illustration of FIG. 12 results in that the propulsion force isreduced toward 0, and accordingly a very low tensile force occurs on thepoint of application of force. Such a modification can also be adjustedin other situations of danger such as by means of the at least onesensor string already mentioned in the general part of the description.

[0142]FIG. 13 shows in a diagrammatic form a sheet element 1 having fouraerodynamically effective pivotable elements 32 in all which can bepivoted individually or together such that they are allowed to actsimilar to flaps and horizontal stabilizers known from aircrafts inorder to be able to be used for a selective motion of the sheet element1 in the vertical and horizontal direction when a determined pivotingangle is adjusted with respect to the surface of the sheet element 1. Tothese elements 32, for example, adequate ropes can be attached by meansof which the angle of attack can be adjusted. In the cases in whichthese elements 32 engage the remaining part of the sheet element 1 in atwo-dimensional manner they are ineffective.

[0143] With these aerodynamically effective elements 32 the Ca/Cd ratiocan be influenced as well to manipulate the propulsion in the eachdesired form.

[0144] With FIG. 14 the effect and function of sling elements 35 forstay ropes shall be explained in a diagrammatic form. On that occasion,merely one such element 35 which is present in a rod-shaped manner onthe body 3 of the watercraft is shown with its effect and function foronly one stay rope 2. A stay rope 2 is illustrated with the solid lineswhen the sheet element 1 is positioned into the wind such that thewatercraft is on the desired course that means it is moved in thedesired direction of motion. If the sheet element 1 is now drifting,however, the equivalent stay rope 2 is moving therewith and is touchingthe sling element 35 for stay ropes, and the drifting motion will belimited correspondingly which necessarily results in a motion of thesheet element 1 into the direction opposite thereto without requiringany engagement manually or by means of another steering possibility.

[0145] Of course, a plurality of such sling elements 35 for stay ropescan be present in the form not shown. These are also allowed to beemployed in pairs for one stay rope 2 each to limit the drifting motionof the sheet element 1 in two directions.

[0146] However, sling elements 35 for stay ropes are also allowed to beformed in a bundle shaped manner as already mentioned in the generalpart of the description.

[0147] In FIG. 15 a wind-propelled vehicle 3 is shown in a verysimplified manner which is connected to a sheet element 1 being similarto a kite through at least one stay rope 100 such that the wind forcesattacking the sheet element 1 can be used for the propulsion of the body3 of the watercraft.

[0148] In FIG. 16 a sheet element 1 is shown with a compressed gascontaining chamber 7 which comprises a connecting branch 108. Theconnecting branch 108 can be connected to a conduit 111 which thecompressed gas containing chamber 7 can be charged through with a gaswhich is preferably helium such that by means of the charged compressedgas containing chamber 7 a lift component can be achieved which issufficient to balance the gravitational force acting upon the sheetelement 1.

[0149] The connecting branch 108 is allowed to be desiged in the form ofa conventional quick acting closure, for example, which should be ableto be locked after charging the compressed gas containing chamber 7 suchthat the first conduit 111 (not shown herein) can be released again fromthe connecting branch 108 after charging the compressed gas containingchamber 7, and the connection will be provided again only if the gas isto be recirculated again from the compressed gas containing chamber 7.

[0150] In FIG. 17 an embodiment is shown in a diagrammatic form howcompressed gas can be directed from a compressed gas accumulator 104into the compressed gas containing chamber 7 of the sheet element 1after opening the valve 102 which is disposed in a first conduit 111. Onthat occasion, the valve 105 disposed in the second conduit 103 which isput around the valve 102 in the form of a by-pass, is closed.

[0151] For recirculating the gas from the compressed gas containingchamber 7 into the compressed gas accumulator 104 the valve 102 will beclosed, and the valve 105 in the second conduit 103 will be openedwherein preferably a force of expansion can be exerted upon thecompressed gas containing chamber 7 at least to assist the recirculationof the gas from the compressed gas containing chamber 7 into thecompressed gas accumulator 104.

[0152] In FIG. 18 is shown another embodiment of gas supply andrecirculation from a compressed gas accumulator 104 into a compressedgas containing chamber 107 and vice versa. Here, two conduits 111 and103 are connected in parallel to each other to the compressed gasaccumulator 104 and the compressed gas containing chamber 7. The gascontained in a compressed form within the compressed gas accumulator 104is allowed to pass into the compressed gas containing chamber 7 afteropening the valve 102, and can be temporarily stored there and used forthe lift of the sheet element 1.

[0153] When the compressed gas containing chamber 7 is to be dischargedeither the connection through the conduit 111 is separated wherein thiscan achieved by closing the valve 102, and simultaneously the compressor107 which is connected with its induction side to the compressed gascontaining chamber side is switched on and the gas can be pumped fromthe compressed gas containing chamber 7 into the compressed gasaccumulator 104.

[0154] The embodiment according to FIG. 19 is modified with respect tothe embodiment according to FIG. 18 in that the conduit 103 is formed asa by-pass around the valve 102. However, in the form not shown asalready explained in the general part of the description the valve 102and compressor 107 as well as the conduits 111 and 103 can be exchanged.

[0155] In FIG. 19 is also indicated that at least one area 111′ of thefirst conduit 111 can be formed in a flexible manner.

[0156] In FIG. 20 is shown an embodiment of a gas supply andrecirculation device having two compressed gas accumulators 104 and 114.

[0157] On that occasion, it deals with a compressed gas accumulator 104with higher internal pressure which the compressed gas containingchamber can be charged from after opening the valve 102 in the firstconduit 111.

[0158] With the closed valve 102 and the opened valve 105 in the secondconduit the gas which is adequately compressed in the compressed gascontaining chamber 7 is allowed to be recirculated into the secondcompressed gas accumulator 114 and temporarily stored there withrelatively low pressure, wherein the internal volume of the compressedgas accumulator 114 is preferably allowed to be relatively great withrespect to that of the compressed gas accumulator 104. From thiscompressed gas accumulator 114 the temporarily stored gas from the lowpressure gas accumulator 114 into the compressed gas accumulator 104 canbe subsequently compressed and replenished, at a suitable time afterswitching oh the compressor 107 which is connected with its inductionside to the compressed gas accumulator 104 and with its delivery side tothe compressed gas accumulator 104.

1. A wind-propelled watercraft having a sheet element which is held withat least one stay rope in close proximity to the body of the watercraft,and said stay rope(s) is (are) attached to at least three points spacedapart from each other on said sheet element (1), characterized in thatthe point (4) of application of force of the stay rope(s) on the body(3) of the watercraft is variable depending on the wind direction andmotion.
 2. A watercraft according to claim 1, characterized in that saidsheet element (1) is made of a flexible material.
 3. A watercraftaccording to claims 1 or 2, characterized in that on said sheet elementat least one compressed gas containing chamber (7) is formed and/orattached thereto.
 4. A watercraft according to any one of claims 1 to 3,characterized in that said compressed gas containing chamber(s) (7)is/are charged with compressed gas having a density which is lower thanair.
 5. A watercraft according to any one of claims 1 to 3,characterized in that on the compressed gas containing chamber(s) (7)there are apertures for charging using the dynamic pressure of wind. 6.A watercraft according to any one of claims 1 to 5, characterized inthat said stay rope(s) (2) is/are held with an element (5) for varyingthe length of said stay rope(s) (2) between said sheet element (1) andsaid body (3) of the watercraft on said body (3) of the watercraft.
 7. Awatercraft according to claim 6, characterized in that said each stayrope (2) is individually held on said body (3) of the watercraft withsaid element (5) for varying its length.
 8. A watercraft according toclaim 1, characterized in that said point (4) of application of force isvariable along a guide (8, 9) attached to said body (3) of thewatercraft.
 9. A watercraft according to claim 1, characterized in thatsaid point (4) of application of force is excentrically disposed on arotary table (11) attached to said body (3) of the watercraft.
 10. Awatercraft according to claim 1, characterized in that said point (4) ofapplication of force is disposed on a pivotable jib boom (10) attachedto said body (3) of the watercraft.
 11. A watercraft according to anyone of claims 1 to 10, characterized in that said point (4) ofapplication of force is variable with respect to the lateral strainingpoint of said body (3) of the watercraft.
 12. A watercraft according toany one of claims 1 to 11, characterized in that said point (4) ofapplication of force is variable in parallel and/or orthogonally withrespect to the longitudinal axis of the watercraft.
 13. A watercraftaccording to any one of claims 1 to 12, characterized in that the lengthof each said stay rope (2) is individually variable.
 14. A watercraftaccording to any one of claims 1 to 13, characterized in that each saidstay rope (2) is wound up on a separate pulley (5).
 15. A watercraftaccording to any one of claims 1 to 14, characterized in that said stayropes (2) are guided over at least one deflection pulley (6).
 16. Awatercraft according to claim 15, characterized in that said deflectionpulley(s) (6) is (are) movable.
 17. A watercraft according to any one ofclaims 1 to 16, characterized in that said three stay ropes (2) are heldon the body (3) of the watercraft and attached to said sheet element (1)at three points spanning a triangle.
 18. A watercraft according to anyone of claims 1 to 16, characterized in that said four stay ropes (2)are held on said body (3) of the watercraft and attached to said sheetelement (1) at four points spanning a rectangle.
 19. A watercraftaccording to any one of claims 1 to 18, characterized in that saidcompressed gas containing chamber(s)(7) is (are) formed at the edge ofsaid sheet element (1).
 20. A watercraft according to any one of claims1 to 19, characterized in that the lifting force of said compressed gascontaining chamber(s) (7) is greater than or equal to the weight of thesheet element (1).
 21. A watercraft according to any one of claims 1 to20, characterized in that at least one hydrodynamically effectiveelement (31) is arranged on said body (3) of the watercraft.
 22. Awatercraft according to claim 21, characterized in that said element(s)(3) is (are) pivotable about an axis.
 23. A watercraft according to anyone of claims 1 to 22, characterized in that the pivoting angle of saidelement(s) (31) is adjustable depending on the velocity of thewatercraft and/or the tensile force of said sheet element (1).
 24. Awatercraft according to any one of claims 1 to 23, characterized in thaton said sheet element (1) at least one aerodynamically effectivelypivotable element (32) is present.
 25. A watercraft according to any oneof claims 1 to 24, characterized in that a leeboard attached to saidbody (3) of the watercraft is rotatable with respect to the longitudinalaxis.
 26. A watercraft according to any one of claims 1 to 25,characterized in that at least one sensor string guided toward said body(3) of watercraft is attached to said sheet element (1).
 27. Awatercraft according to any one of claims 1 to 26, characterized in thatelements protecting from overload are present on said stay rope(s) (2).28. A watercraft according to any one of claims 1 to 27, characterizedin that wind stall elements are present at the outer edges of said sheetelement (1).
 29. A watercraft according to any one of claims 1 to 28,characterized in that stay rope sling elements (35) are present on saidbody (3) of the watercraft.
 30. A wind propulsion according to any oneof claims 1 to 29, characterized in that at least said one compressedgas containing chamber (7) can be connected to at least one compressedgas accumulator (104) by means of one first conduit (111) and one valve(102), and said compressed gas containing chamber (7) can be chargedfrom said gas accumulator (104).
 31. A wind propulsion according toclaim 30, characterized in that a second conduit (103) which can beconnected to said compressed gas containing chamber (7) or which isconnected to said first conduit (111) is present for the recirculationof gas from said compressed gas containing chamber (7) into at leastsaid one or a second compressed gas accumulator (104, 114).
 32. A windpropulsion according to claims 30 or 31, characterized in that at leastsaid first conduit (111) is regionally formed in a flexible manner. 33.A wind propulsion according to any one of claims 30 to 32, characterizedin that a compressor (107) is provided in an in-line arrangement withsaid second conduit (103).
 34. A wind propulsion according to any one ofclaims 20 to 33, characterized in that in said first compressed gasaccumulator (104) a pressure of said compressed gas, which is greaterthan or equal to the internal pressure in said compressed gas containingchamber (7), is met.
 35. A wind propulsion according to any one ofclaims 30 to 34, characterized in that the induction side of saidcompressor (107) is mounted to said compressed gas containing chamber(7), and the delivery side thereof is mounted to said compressed gasaccumulator (104, 114) in said second conduit (103).
 36. A windpropulsion according to any one of claims 30 to 35, characterized inthat said second conduit (103) with said compressor (107) is connectedto said first conduit (111) in the form of a by-pass around said valve(102).
 37. A wind propulsion according to any one of claims 30 to 35,characterized in that said first conduit (111) is guided around saidcompressor (107) as a by-pass, and a two-way valve is arranged in saidfirst conduit (111).
 38. A wind propulsion according to any one ofclaims 30 to 37, characterized in that said compressed gas containingchamber (7) and said compressed gas accumulator (104) are charged with agas which has a density lower than gas.
 39. A wind propulsion accordingto any one of claims 30 to 38, characterized in that at least said onecompressed gas accumulator (104, 114) can be attached to the watercraft.40. A water craft according to any one of claims 30 to 38, characterizedin that on said compressed gas containing chamber (7) at least onelockable connecting branch (108) is present for said first conduit(111).